The RAP expeditions typically send large teams of scientists into remote habitats for intense, monthlong surveys.
"We go out and explore so that we can bring a wide range of new species—1,300 so far—and thousands of other rare and really interesting species to the public and policy makers," explained RAP director Leeanne Alonso.
"Showing people what's there helps us make the best decisions about how to manage areas to keep these species around, while continuing the benefits that humans get from these places."
In other words: Help us, they will.
Photograph courtesy Piotr Naskrecki, Conservation International
Emperor of the Scorpions
Pictured during a 2006 RAP expedition in Ghana, Africa's emperor scorpion is one of the world's biggest—but not baddest.
The 8-inch-long (20-centimeter-long) arachnids are venomous, but their venom isn't particularly harmful to people—and may even be helpful.
It contains compounds currently being tested for use in future drugs to battle heart ailments including arrhythmia, according to Conservation International.
A living relative of chinchilla rats found buried alongside humans in ancient Inca tombs, the chinchilla tree rat species was discovered during RAP expeditions in mountains near Peru's Machu Picchu in 1997 and 1998.
More than just a new species, the rat represents an entirely new genus—giving scientists hope that other, similar rat species may still await discovery.
Named for its discoverers, the Conservation International blattodean insect was found in 2002 in a single cave in Guinea's Simandoa Range—still the only place this African cockroach relative is known to live.
Conservation International's "new mission is demonstrating that nature provides ecosystem services that benefit humans," Alonso said, noting that the blattodean is a prime example.
"People don't like cockroaches, but they provide a very important service in breaking down detritus into nutrients."
Atewa dinospiders are part of an arachnid lineage that's hardly changed in 300 million years—before dinosaurs walked the Earth.
Feeding on tiny termites and ant larvae, the crablike creature lives in Ghana's Atewa Range Forest Reserve, where the species was discovered in 2006. At just 0.4 inch (11 millimeters) wide, the Atewa dinospider is still the biggest living member of its small group of 57 known species.
Hailing from Cambodian forests, this large (0.6-inch-long/1.5-centimeter-long) fishhook ant pierces predators with its curved spines, which can also form a sort of home-security system.
“When they get disturbed, they will run all around, and the hooks get stuck together, so they form a kind of dense, defensive mat above the nest. It can be effective though maybe not intentional,” Alonso said.
In a twist on the usual tale, this new species actually found Conservation International scientists, rather than vice versa. The so-called Pinocchio frog turned up on a bag of rice at a RAP expedition campsite in Indonesia's remote Foja Mountains in 2008.
The frog's long nose protuberance stands upright when a male is calling but deflates and hangs downward during inactive times. Scientists are still sorting out the purposes of the unusual appendage.
This 6-inch-long( 15-centimeter-long) tree frog has big eyes to boot—the better to survey the high wilderness in Papua New Guinea, where the new species was found in 2008 next to a mountain river.
Like other species of the Nyctimystes genus, the newfound frog lays eggs under the stones of clear, running waters. After tadpoles hatch, they use enormous sucker-like mouths to attach themselves to streambed rocks and graze without being swept away. (See pictures of tree frog tadpoles.)
Boasting a leg span of nearly a foot (30 centimeters) and tipping the scales at some 6 ounces (170 grams), Guyana's goliath bird-eating spider is the heaviest spider species in the world. (See video of the biggest spider in the world.)
This gola malimbe bird was spotted in southeastern Guinea's Diecke Forest, home to one of the three known populations of the species.
The bird is among thousands of rarely seen species—1,300 entirely new to science—that RAP surveys have spotted over the past 20 years.
Conservation International founder Peter Seligmann has described a typical RAP expedition as "an ecological SWAT team that could accurately assess the health of an ecosystem in a fraction of the time it would normally take."
Entomologist Piotr Naskrecki discovered, named, and photographed the so-called RAP katydid, or Brachyamytta rapidoaestima, on a 2002 survey in Ghana and Guinea. The ambush predators typically cling to the undersides of leaves and wait for unfortunate insects to land above.
Naskrecki, director of Conservation International's Invertebrate Rapid Assessment Program, "named this species after RAP because it lives in West African forests that are being rapidly destroyed.
"We're focusing on getting in there rapidly to learn what's there and try to save things before they are gone," Alonso said.
Discovered in Indonesia in 2006, this new species of flasher wrasse, Paracheilinus nursalim, is notable for a colorful courtship ritual. Male fish flash "electric" colors (pictured) to get the attention of nearby females.
Males don't mate and run, however—father fish are known to guard eggs and sometimes even larvae.
The wattled smoky honeyeater was found in 2005 in Indonesia's Foja Mountains, where the new species lives at lofty altitudes some 5,445 feet (1,650 meters) above sea level.
As its name suggests, the honeyeater does indeed eat nectar, and so plays an important role in pollinating flowers. Despite the bird's importance, the species maintains a low profile and has rarely been heard vocalizing.
This new species of suckermouth catfish, Pseudancistrus kwinti, can attach itself to mid-stream objects even in fast-flowing waters of Suriname's Coppename River, where the species was first found in 2005.
The South American fish uses its mouth and teeth to feed on a smorgasbord of invertebrates, detritus, and algae by rotating its upper and lower jaws to scrape the substrate for tasty morsels.
This tiger ant species was spotted in Papua New Guinea in 2009.
"It's fascinating that it's striped like a tiger," Alonso said. "When [you look] inside the rotting twigs where it lives, you can see why—the twig looks like that too, because parts of it are rotten or moldy, so it really blends in."
The tiny ant is also a formidable predator for its size, using its lightning-quick mandibles to snare small invertebrates. Ants also use their jaws to carry their own pupae, as seen in this image.
A walking shark prowls the floor of Indonesia's Cenderawasih Bay in 2006. Though the new species can swim, it often use its fins to "walk" along reefs and feast on small fish, crabs, snails, and shrimp. (Video: Watch the walking shark walk.)
One of the biggest sensations of the first 20 years of RAP research, the walking shark intrigues scientists as well as the public. Biologists believe that walking sharks may be models for the first animals that made the transition from sea to land.